My wife and I enjoy the wedge the best. Still, the ramp is great, however, I find that is just to large and takes up too much space on the bed and in the closet!
Oh, and we bought the axis- but were disappointed with its size. Instead of being too large, it was a bit too small. Thankfully, we noticed the size issue before we took it out of the packaging!
Also, we have the escape wet- but hardly use it. I think it's been used once. Pity.